1. Field of the Invention
The present invention relates to specimen inspection systems and, more particularly, to specimen inspection systems that can discriminate between materials having similar densities.
2. Description of Related Art
The food inspection industry currently uses x-ray based systems that employ scintillator/photodiode linear arrays to verify portions and fill height, inspect food and packaging quality, identify food contaminants, and/or provide process control. These systems rely on the ability to detect the x-ray transmissive differences between food, packaging, and contaminants present. These systems are effective for inspecting products that have significantly different densities between the food product and the packaging or contaminant(s). However, where the contaminant(s) and/or packaging are similar in density to the food being inspected, the accuracy of the system to detect differences is compromised.
Accordingly, what is needed is an x-ray system and method of use thereof for use in the food inspection industry that can detect differences between the food being inspected and any contaminant(s) present in the food and/or the food packaging, especially where the contaminant(s) and/or packaging are similar in density to the food being inspected.
Examples of uses of x-rays for detecting differences between two or more constituent of a body can be found in the following articles: “The Potential for Compton Scattered X-rays in Food Inspection: The Effect of Multiple Scatter and Sample Inhomogeneity” by N. J. B. McFarlane, C. R. Bull, R. D. Tillett, R. D. Speller, G. J. Royle and K. R. A. Johnson, J. agric. Engng Res. (2000) 75, 265-274; “Energy-dispersive x-ray diffraction tomography” by G. Harding, M. Newton and J. Kosanetzky, Phys, Med. Biol., 1990, Vol. 35, No 1, 33-41; “Time Constraints on Glass Detection in Food Materials using Compton Scattered X-rays” by N. J. B. McFarlane, C. R. Bull, R. D. Tillett, R. D. Speller and G. J. Royle, J. agric. Engng, Res. (2001) 79(4), 407-418; and “Energy Dispersive X-ray Scatter for measurement of oil/water ratios”, University of Surrey, Department of Physics Radiation Imaging, http://www.ph.surrey.ac.uk/rmm/imaging/xray_scatter/index.html.